The present invention relates generally to lighting devices and methods for illumination and more particularly to linear lighting devices for wide area light distribution.
Conventional linear lighting devices for wide area light distribution are used in a variety of lighting applications, such as in outdoor lighting, indoor lighting, overhead lighting, luminaires, roadway lighting, and for illuminating sign boxes and other backlit applications. Linear wide area lighting devices operate to emit light over a wide area using an elongated emitter array. This may be achieved using a variety of lighting device configurations. Typically, linear wide area lighting devices include numerous light emitters such as a light emitting diode and an optic, or lens, to distribute the light from the emitters in a desired illumination profile. Some conventional linear wide area lighting devices include lenses having a three-dimensional light refraction profile to achieve light distribution across a wide area in an illumination space. However, lenses having three dimensional lighting profiles are generally more difficult and expensive to manufacture than longitudinal lenses which refract light in two dimensions as opposed to three dimensions.
Linear wide area lighting devices of this nature are commonly arranged in longitudinal strips or strands of lights that may be arranged in a linear or semi-linear orientation. Multiple strands may be positioned together in an end-to-end configuration or in a side-by-side configuration depending on the particular application. For example, devices for illuminating sign boxes include one or more longitudinal light devices arranged on the interior of a sign box or other enclosure. Multiple devices are added for larger enclosures.
Conventional linear wide area lighting devices also include numerous lighting modules wired together in series. Each module includes multiple emitters and individual optics. Such configurations are costly to manufacture as each module has its own independent set of parts including housing, lens, circuit board, etc., resulting in a high number of parts for a single linear lighting application. Additionally, such configurations require independent fasteners for each module within a fixture or other mounting application, and each module spans only a relatively small distance compared to the overall linear lighting dimension.
Each device in a conventional linear wide area lighting device typically includes multiple light emitters. Emitters may take many forms, including but not limited light emitting diodes, conventional bulbs, lamps, or other emitters. Each emitter is connected to an electrical circuit included on the device. In some applications, multiple light emitting diodes are positioned on one or more substrates and are connected to a light emitting diode driver circuit to provide power and control for illumination. One or more lenses are positioned over each emitter to provide distribution of the emitted light across a wide area. Each lens may be shaped to provide a desired illumination profile. High part counts and module counts associated with conventional lighting devices, combined with complex lens geometries for three-dimensional light distribution, result in complex designs and high costs of manufacturing. Additionally, using conventional modular linear systems, numerous modules are required to achieve a desired luminance output.
What is needed then are improvements in linear lighting devices and systems for wide area light distribution.